JP2779754B2 - New synthetic lubricating oil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbonate compound having extremely excellent hydrolysis stability against acids and alkalis, such as rolling oil, cutting oil, grinding oil, drawing oil, and press oil. It can be used for metal working oils and metal plastic working oils and lubricating oils having good friction and wear resistance during sliding.

[0002]

2. Description of the Related Art Lubricating oils are widely used in various industrial fields, and are mainly used for the purpose of reducing friction and abrasion on a contact surface at the time of metal working or contact sliding between metals. The physical properties required for the lubricating oil vary depending on the field of use, but generally include lubricity, oxidation stability, heat stability, low-temperature fluidity, viscosity characteristics, and the like.

[0003] In order to satisfy such performance, conventionally, as base oils and additives of various lubricating oil compositions, mineral oils, animal and vegetable oils and fatty acids derived from animal and vegetable oils and fats are used in natural products, and α-olefin oligomers are used in synthetic products. , Polyalkylene glycols, fatty acid monoesters and diesters, polyol esters, phosphate esters, silicate esters, silanes, silicones, polyphenyl ethers, fluorocarbons, and the like are used. It has been practically used as a lubricating oil composition.

[0004] Concretely, in the case of cold rolling oil used for a thin steel sheet, a base oil based on animal and vegetable fats (tallow, lard, soybean oil, rapeseed oil, palm oil, coconut oil, etc.) and a base oil based on mineral oil Are roughly divided into In general, rolling oils based on mineral oils are used to enhance rolling lubricity. In order to enhance rolling lubricity, animal and vegetable fats and oils and fatty acids (capric acid, lauric acid, myristic acid, stearic acid, oleic acid, linolenic acid, etc.) or esters (trimethylolpropane, Oily improvers such as monoesters, diesters, and synthetic esters such as polyesters of carboxylic acids with alcohols such as pentaerythritol and 2-ethylhexyl alcohol are used.

On the other hand, lubricating oils used for metal cutting and grinding are mineral oil, animal and vegetable fats and oils, extreme pressure additives, surfactants, defoamers, metal anticorrosives, antioxidants, preservatives, and fungicides. Are appropriately mixed according to the purpose. The cutting fluid is usually used after being diluted 10 to 100 times with water, but in some cases, a non-aqueous cutting fluid may be used. The basic conditions that the cutting oil should have are: lubricity, cooling, rust prevention and other incidental conditions, such as foaming,
It does not have rough hand, toxicity to humans, odor, etc. Cutting grinding fluids must have the above-mentioned performances in a well-balanced manner, even if the emphasis is different depending on the purpose of use and conditions, but cutting grinding fluids that can sufficiently satisfy these have not yet been put to practical use. Is the current situation.

[0006]

That is, with the diversification and sophistication of the industrial field in recent years, the use conditions of lubricating oils have become severe, and the performance required by conventional synthetic lubricating oils has been sufficiently improved. It is getting harder to meet. Specifically, a strongly acidic (pH 2 to 3) region or a strongly alkaline (pH 11)
In the case of using a lubricating oil in an emulsion under the environment of the 〜12) region, higher hydrolysis resistance is required. Further, when used at high temperatures, lubricating oils having good thermal stability are required. Accordingly, an object of the present invention is to provide a synthetic lubricating oil having good lubricating properties, and excellent hydrolysis resistance in a strongly acidic and strongly alkaline region and excellent thermal stability.

[0007]

Means for Solving the Problems The present inventors have made intensive studies in order to achieve the above object, and as a result, have found that a lubricating oil containing a specific polycarbonate compound is suitable for this, and complete the present invention. Reached. That is, the present invention
It is a synthetic lubricating oil containing a polycondensate of a divalent carbonate and a monohydric alcohol with a divalent carbonate and a divalent carbonate having a tertiary nitrogen. The polycondensate of the present invention is one kind of a so-called polycarbonate compound, and may be one obtained by simultaneously reacting the above-mentioned amino polyol, dialkyl carbonate and monohydric alcohol, but desirably the reactant of amino polyol and dialkyl carbonate is used. It is preferable to react with a monohydric alcohol.

The tertiary nitrogen-containing di- to tetra-valent amino polyols used for synthesizing the polycondensate of the present invention are mainly represented by the following general formulas (A), (B), (C), (D) or ( It is preferable that one or more kinds of E) are used.

[0009]

Embedded image

Embedded image

Embedded image

Embedded image

Embedded image

In the above formulas (A) to (E), R _{1 is} an alkyl, alkenyl, cyclohexyl or phenyl group having 1 to 20 carbon atoms. R ₂ : an alkyl group having 1 to 6 carbon atoms, a cyclohexyl group,
Or a phenyl group. X: H or methyl group. n: an integer of 1 to 3.

That is, all of the above amino polyols have in common an-(CH ₂ CXHO) n -H group (where X = H or a methyl group, n = 1 to 3) as an alcohol part. Among them, the dihydric amino alcohols represented by the general formula (A) are monoamine type diols having an alkyl group, alkenyl group, cyclohexyl group or phenyl group having 1 to 20 carbon atoms as R ₁ , such as methyldiethanolamine, methyl Diisopropanolamine,
Ethyldiethanolamine, propyldiethanolamine, propyldiisopropanolamine, butyldiethanolamine, butyldiisopropanolamine, cyclohexyldiethanolamine, and cyclohexyldiisopropanolamine are preferably used. In addition, ethylene oxide 2-mol addition dodecylamine, propylene oxide 3-mol addition octadecylamine, tallow alkyldiisopropanolamine, and the like can also be used.

The dihydric amino alcohol represented by the general formula (B) is a piperazine of a diamine type diol, such as N, N'-bis (2-hydroxyethyl) piperazine, N, N'-bis (2- (Hydroxypropyl) piperazine, N, N′-bis (2-hydroxyethyl) -2-
Methylpiperazine, N, N'-bis (2-hydroxypropyl) -2-methylpiperazine are preferred. N, N '
-Bis (ethylene oxide 2 mol addition) piperazine,
N, N'-bis (propylene oxide 3 mol addition) piperazine or the like may be used. The trihydric amino alcohol represented by the general formula (C) is a monoamine type triol, and for example, triethanolamine and triisopropanolamine are preferable. In addition, ethylene oxide 3 mole addition monoamine, propylene oxide 2 mole addition monoamine and the like can also be used.

The trihydric amino alcohol represented by the general formula (D) is a triamine-type triol isocyanurate, for example, tris (2-hydroxyethyl) isocyanurate and tris (2-hydroxypropyl) isocyanurate are preferable. Also, tris (propylene oxide 3 mol addition) isocyanurate may be used. The tetravalent amino alcohol represented by the general formula (E) is a diamine type tetraol having an alkyl group having 1 to 6 carbon atoms, a cyclohexyl group, or a phenyl group as R ₂ , for example, N, N ′, N, N '-Tetrakis (2-hydroxypropyl) ethylenediamine, N, N', N, N'-tetrakis (2-hydroxyethyl) phenylenediamine are preferred. Also, N, N ', N, N'-tetrakis (2-
Hydroxyethyl) hexylenediamine, N, N ',
N, N'-tetrakis (addition of 2 moles of ethylene oxide) ethylenediamine and the like can also be used.

In addition to the above-mentioned various amino polyols,
Amino polyols such as polyoxyethylene octadecylamine and polyoxypropylene tallow alkylamine can also be used as raw materials in the present invention.

The dialkyl carbonate preferably has a lower alkyl group having 1 to 6 carbon atoms, and specific examples thereof include dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, dihexyl carbonate and the like. And dicyclohexyl carbonate can also be used. In the present invention, a dialkyl carbonate having an alkyl group having more than 6 carbon atoms may be used. However, in this case, the reaction does not easily proceed and tends to be difficult to remove as an unreacted substance.

The monohydric alcohol preferably has 5 to 50 carbon atoms and has a linear or side chain alkyl group, alkenyl group or aryl group. Specific examples thereof include amyl alcohol, hexanol, heptanol and octanol. , Nonanol, decanol, lauryl alcohol, tridecanol, myristyl alcohol, cetanol, stearyl alcohol, oleyl alcohol, eicosenol, hysokol 246 (side chain mixed alcohol having 24 to 26 carbon atoms, manufactured by Ito Oil Co., Ltd.), NJ Coal 3236 (Chain having 32 to 36 carbon atoms, side chain mixed alcohol, manufactured by Nippon Rika Co., Ltd.), Unilin alcohol 550
(Linear mixed alcohol having 50 carbon atoms, manufactured by Petrolite Co., USA), benzyl alcohol and the like.

In synthesizing the polycondensate of the present invention, the mixing ratio of the raw materials, that is, the reaction molar ratio may be appropriately selected, and the amino polyol is represented by the general formula (A) or (B). Preferably, the amino polyol / dialkyl carbonate / monohydric alcohol = 1/2
/ 2 to 2/3/2, and when the amino polyol is represented by the general formula (C) or (D), preferably the amino polyol / dialkyl carbonate / monohydric alcohol = 1/3/3 to When the amino polyol is represented by the general formula (E), the amino polyol / dialkyl carbonate / monohydric alcohol is preferably 〜 / 4/4 to 5/18/14.
It is. When aminopolyols are used as a mixture of two or more, they may be set with reference to such a mixing ratio.

In the present invention, the polycondensation reaction preferably employs the following two-step reaction. That is, first, a first-stage reaction is performed between the amino polyol and a dialkyl carbonate, and then a second-stage reaction is performed between the reaction product and a monohydric alcohol. In the first stage reaction, the dialkyl carbonate may be added to the amino polyol at a set molar equivalent, but the azeotropic distillation with the alcohol by-produced from the dialkyl carbonate uses a dialkyl carbonate of 1.2 to 1.5 times the set molar equivalent. Is good. In the second-stage reaction, a set molar equivalent of a monohydric alcohol is added to the reaction product of the first-stage reaction, and when the theoretical amount of alcohol is distilled off, the reaction is terminated, and unreacted dialkyl carbonate is removed under normal pressure or reduced pressure. By distillation, the polycondensate of the present invention can be obtained.

The reaction temperature is from 90 ° C. to 200 ° C., which is near the boiling point of dialkyl carbonate.
Known transesterification catalysts can be used for such a reaction, for example, lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, zinc, aluminum, titanium,
What is necessary is just to select suitably from metals, such as cobalt, germanium, tin, lead, antimony, arsenic, and cerium, and these alkoxides.

2 to 4 having tertiary nitrogen thus obtained
Polycondensates of divalent amino polyols, dialkyl carbonates and monohydric alcohols, as such, or as required, known mineral oils, animal and vegetable oils and fats, fatty acids, extreme pressure additives, as long as they do not depart from the scope of the objects of the present invention, A lubricating oil can be formed by adding a surfactant, an antifoaming agent, a metal anticorrosive, an antioxidant, a preservative, a fungus and the like. The blending amount of the polycondensate in the lubricating oil of the present invention varies depending on the use, purpose and use of the lubricating oil, but is generally 0.1 to 50% by weight, preferably 1 to 30% by weight.

[0021]

EXAMPLES In the following Synthesis Examples and Examples, parts are shown by weight. Synthesis Example 1 stirrer, 1 liter four-necked flask butyl diethanolamine 219 parts of a thermometer (2 mol), dimethyl carbonate 184 parts (3 moles), and 0.06 parts of titanium tetraisopropoxide as a catalyst Preparation, 90 ° C
For 4 hours. After cooling, additional nonanol 196
The reaction was continued at 150 ° C. for 3 hours until the theoretical amount of ethanol was distilled off, and unreacted nonanol was distilled off under reduced pressure to obtain a polycondensate of the present invention. Theoretical molecular weight
Is 501, the saponification value is 489, and the estimated molecular weight is 459.
Was.

Synthesis Example 2 N, N-bis (2-hydroxyethyl) piperazine 17 was placed in a 1-liter four-necked flask equipped with a stirrer and a thermometer.
4 parts (1 mol), 228 parts of dipropyl carbonate (2
Mol), and sodium methylate 0.01 as a catalyst.
And then reacted at 120 ° C. for 4 hours. After cooling, 564 parts (2 moles) of oleyl alcohol were further added, and 1
The reaction was carried out at 50 ° C. for 5 hours until the theoretical amount of propanol was distilled off to obtain a polycondensate of the present invention. Theoretical molecular weight 73
4. Saponification value 310 and estimated molecular weight was 724.

Synthesis Example 3 A 1-liter four-necked flask equipped with a stirrer and a thermometer was charged with 137 parts (4 mol) of triethanolamine, 244 parts (9 mol) of diethyl carbonate, and 0.02 part of magnesium as a catalyst. The reaction was carried out at 6 ° C. for 6 hours. After cooling, 213 parts (5 moles) of lauryl alcohol were further added and reacted until a theoretical amount of ethanol was distilled off, and unreacted carbonate and lauryl alcohol were distilled off under reduced pressure to obtain a polycondensate of the present invention. . The theoretical molecular weight is 117
2, the saponification value was 558, and the estimated molecular weight was 1006.

Synthesis Example 4 Tris (2-hydroxyethyl) isocyanurate 290 was placed in a 1-liter four-necked flask equipped with a stirrer and a thermometer.
Parts (3 mol), 167 parts (5 mol) of dimethyl carbonate, and 0.03 part of titanium tetraisopropoxide as a catalyst were charged and reacted at 90 ° C. for 5 hours. After cooling, 144 parts (3 mol) of 2-ethylhexanol was further added, and the mixture was reacted at 200 ° C. for 5 hours until the theoretical amount of methanol was distilled off, and unreacted carbonate and 2-ethylhexanol were distilled off under reduced pressure. Thus, the polycondensate of the present invention was obtained. Estimated molecule with theoretical molecular weight of 729 and saponification value of 430
The amount was 783.

Synthesis Example 5 117 parts (2 moles) of ethylenediaminetetraisopropanol, 160 parts (7 moles) of di-n-propyl carbonate, and 0.1 ml of sodium methylate as a catalyst were placed in a 1-liter four-necked flask equipped with a stirrer and a thermometer. 03 parts were charged and reacted at 120 ° C. for 4 hours. After cooling, 324 parts (6 mol) of isostearyl alcohol was further added and reacted until a theoretical amount of propanol was distilled off. Unreacted carbonate and isostearyl alcohol were distilled off under reduced pressure to obtain the polycondensation of the present invention. Was. The theoretical molecular weight is 23
92, a saponification value of 363, and an estimated molecular weight of 2,164.
Was.

Examples 1 to 5 and Comparative Examples 1 to 3 Test the stability of the polycondensate of the present invention obtained in Synthesis Examples 1 to 5 and three types of fatty acid esters as a comparative example under acidic and alkaline conditions. did. The results are shown in Tables 1 and 2. From both test results, it was revealed that the polycondensate of the present invention has excellent stability against hydrolysis in acidic and alkaline conditions.

[Test method for acid hydrolysis stability] About 2 samples
g is weighed correctly into a saponification value measuring flask, and 50 ml of 1 / 3N hydrochloric acid (pH = 0.5) is correctly added thereto. Next, a condenser was attached to the flask and heated at 90 ° C. After heating for a certain period of time, cool, remove the cooler, add a few drops of thymol blue neutral red indicator,
Titrate with 3N potassium hydroxide standard solution. A blank test is performed in parallel with this test. The saponification value was measured at regular intervals, and the acid hydrolysis rate (%) was determined from the following formula. Acid hydrolysis rate (%) = V _a / SV × 100 where V _{a is} the saponification value of the sample after a certain time. SV: saponification value of sample (heated with 1N ethanolic potassium hydroxide solution for 6 hours).

[0028]

[Table 1]

[Test Method for Stability of Alkaline Hydrolysis] Approximately 2 g of a sample was weighed correctly in a flask for measuring saponification value, and 1 / 3N ethanolic potassium hydroxide solution 2 was added thereto.
Add 5 ml correctly. Next, a condenser is attached to the flask, and after heating at 85 ° C. for a certain period of time, the mixture is cooled. The condenser is removed, a few drops of a phenolphthalene indicator are added, and the mixture is titrated with a 1 / 3N hydrochloric acid standard solution. A blank test is performed in parallel with this test. The saponification value was measured at regular intervals, and the alkali hydrolysis rate (%) was determined from the following formula. Alkali hydrolysis rate (%) = _Vb / SV × 100 where _Vb : saponification value of sample after a certain time. SV: saponification value of sample (heated with 1N ethanolic potassium hydroxide solution for 6 hours).

[0030]

[Table 2]

The general properties of the polycondensate of the present invention obtained in Synthesis Examples 1 to 5 and three kinds of fatty acid esters as comparative examples,
The coefficient of dynamic friction and heat resistance as lubricating oil suitability were measured. The dynamic friction coefficient was measured at 25 ° C. using a Soda type pendulum type oil friction tester, and the heat resistance was measured using a thermobalance. Table 3 shows the results. From Table 3, it can be seen that the polycondensate of the present invention has an appropriate viscosity as a lubricating oil base, has a dynamic friction coefficient equal to or less than that of a conventional lubricating oil base, and has excellent heat resistance. Was revealed.

[0032]

[Table 3]

[0033]

According to the present invention, it is possible to provide a synthetic lubricating oil which is excellent in hydrolysis resistance in a strongly acidic and strongly alkaline region and has good lubricity and is used in metal working. The lubricating oil of the present invention has applications such as cold rolling oil for steel sheets and metal cutting and grinding.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C10M 105: 12) C10N 40:02 40:20

Claims (11)

(57) [Claims] 1. The following general formulas (A), (B), (C),
A synthetic lubricating oil comprising a polycondensate of one or more of the amino polyols (D) or (E), a dialkyl carbonate and a monohydric alcohol. Embedded image Embedded image Embedded image Embedded image Embedded image However, in the above formulas (A) to (E), R _{1 is} an alkyl group, alkenyl group, cyclohexyl group or phenyl group having 1 to 20 carbon atoms. R ₂ : an alkyl group having 1 to 6 carbon atoms, a cyclohexyl group or a phenyl group. X: H or a methyl group. n: an integer from 1 to 3. 2. An aminopolyol represented by the general formula (A) is methyldiethanolamine, methyldiisopropanolamine, ethyldiethanolamine, propyldiethanolamine, propyldiisopropanolamine,
The lubricating oil according to claim 1 , which is butyldiethanolamine, butyldiisopropanolamine, cyclohexyldiethanolamine, or cyclohexyldiisopropanolamine. 3. A general formula (B) amino polyol NN represented by ^'- bis (2-hydroxyethyl) piperazine, ^NN' - bis (2-hydroxypropyl) piperazine, NN ^'- bis (2-hydroxyethyl) 2-methyl piperazine, or NN ^'- bis (2-hydroxypropyl) lubricating oil according to claim 1 which is 2-methylpiperazine. 4. The lubricating oil according to claim 1 , wherein the amino polyol represented by the general formula (C) is triethanolamine or triisopropanolamine. 5. The lubricating oil according to claim 1 , wherein the amino polyol represented by the general formula (D) is tris (2-hydroxyethyl) isocyanurate or tris (2-hydroxypropyl) isocyanurate. 6. The aminopolyol represented by the general formula (E) is N, N ′, N, N′-tetrakis (2-hydroxypropyl) ethylenediamine or N, N ′, N, N′-
The lubricating oil according to claim 1 , which is tetrakis (2-hydroxyethyl) phenylenediamine. 7. The dialkyl carbonate has 1 to 6 carbon atoms.
The lubricating oil according to claim 1, wherein the lubricating oil has an alkyl group. 8. The lubricating oil according to claim 1, wherein the monohydric alcohol has 5 to 50 carbon atoms and has a linear or side chain alkyl group, alkenyl group or aryl group. 9. The reaction molar ratio of the amino polyol represented by the general formula (A) or (B), the dialkyl carbonate and the monohydric alcohol is as follows: amino polyol / dialkyl carbonate / monohydric alcohol = 1/2/2 to 2 / 3/2
The lubricating oil according to any one of claims 1, 2, 3, 4, and 8. 10. The reaction molar ratio of the amino polyol represented by the general formula (C) or (D), the dialkyl carbonate and the monohydric alcohol is as follows: amino polyol / dialkyl carbonate / monohydric alcohol = 1/3/3 to 5 / 11
The lubricating oil according to claim 1, wherein the lubricating oil is / 7. 11. The reaction molar ratio of an amino polyol represented by the general formula (E), a dialkyl carbonate and a monohydric alcohol is such that amino polyol / dialkyl carbonate / monohydric alcohol = 1/4/4 to 5/18/14. The lubricating oil according to any one of claims 1, 2, 7, and 8.